Bright Felicity M, Clark Brad, Jay Ollie, Périard Julien D
Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia.
Heat and Health Research Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia.
Scand J Med Sci Sports. 2025 Mar;35(3):e70041. doi: 10.1111/sms.70041.
This study investigated the effects of absolute humidity on heat dissipation and subsequent thermal, cardiovascular, and performance responses during self-paced exercise in the heat. Twelve trained male cyclists performed a 700-kJ time trial in four different humidity conditions (Low: 1.6 kPa, Moderate: 2.5 kPa, High: 3.5 kPa, and Very high: 4.5 kPa) in 33°C. The gradient in partial water vapor pressure at the saturated skin surface and in air, which determines sweat evaporation, decreased significantly with increasing humidity (Low: 3.53 ± 0.30 kPa, Moderate: 2.74 ± 0.24 kPa, High: 1.99 ± 0.20 kPa, Very high: 1.19 ± 0.16 kPa; p < 0.001). The maximum evaporative capacity of the environment (E) also decreased with greater humidity (Low: 309 ± 26 W m, Moderate: 240 ± 21 W m, High: 175 ± 18 W m, Very high: 104 ± 14 W m; p < 0.001), as did sweating efficiency (S) (Low: 0.50 ± 0.13, Moderate: 0.39 ± 0.10, High: 0.28 ± 0.09, Very high: 0.16 ± 0.04; p ≤ 0.003). Power output was similar between Low (260 ± 33 W) and Moderate humidity (257 ± 27 W; p = 0.999), but lower in Very high (222 ± 37 W) than in all other conditions (p < 0.001) and lower in High (246 ± 31 W) than in the Low and Moderate humidity (p < 0.001). Peak core temperature was higher in Very high (39.49°C ± 0.56°C) than in Low (38.97°C ± 0.44°C; p < 0.001), Moderate (39.04°C ± 0.39°C; p = 0.002) and High humidity (39.12°C ± 0.47°C; p = 0.010). Mean skin temperature was higher with elevated humidity (p < 0.001) and mean heart rate was not significantly different between conditions (p ≥ 0.056). These data indicate that reductions in evaporative potential and efficiency with elevated humidity exacerbate thermal and cardiovascular strain during self-paced cycling in the heat, resulting in marked performance impairments.
本研究调查了绝对湿度对热环境下自定节奏运动中散热以及随后的体温、心血管和运动表现反应的影响。12名受过训练的男性自行车运动员在33°C的环境中，于四种不同湿度条件下（低湿度：1.6kPa，中等湿度：2.5kPa，高湿度：3.5kPa，非常高湿度：4.5kPa）进行了一次700千焦的计时赛。决定汗液蒸发的饱和皮肤表面与空气中的部分水蒸气压力梯度，随着湿度增加而显著降低（低湿度：3.53±0.30kPa，中等湿度：2.74±0.24kPa，高湿度：1.99±0.20kPa，非常高湿度：1.19±0.16kPa；p<0.001）。环境的最大蒸发能力（E）也随着湿度增加而降低（低湿度：309±26W/m，中等湿度：240±21W/m，高湿度：175±18W/m，非常高湿度：104±14W/m；p<0.001），出汗效率（S）也是如此（低湿度：0.50±0.13，中等湿度：0.39±0.10，高湿度：0.28±0.09，非常高湿度：0.16±0.04；p≤0.003）。低湿度（260±33W）和中等湿度（257±27W；p=0.999）下的功率输出相似，但非常高湿度（222±37W）下的功率输出低于所有其他条件（p<0.001），高湿度（246±31W）下的功率输出低于低湿度和中等湿度（p<0.001）。非常高湿度下的核心体温峰值（39.49°C±0.56°C）高于低湿度（38.97°C±0.44°C；p<0.001）、中等湿度（39.04°C±0.39°C；p=0.002）和高湿度（39.12°C±0.47°C；p=0.010）。随着湿度升高，平均皮肤温度更高（p<0.001），各条件下的平均心率无显著差异（p≥0.056）。这些数据表明，随着湿度升高，蒸发潜力和效率降低，会加剧热环境下自定节奏骑行过程中的体温和心血管压力，导致运动表现明显受损。
